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Monoclonal antibodies (mAbs) constitute the most rapidly growing class of human therapeutics and the second largest class of drugs after vaccines. The treatment of B-cell malignancies and HER2/Neu(+) breast cancer has benefited considerably from the use of therapeutic mAbs, either alone or in combination with standard chemotherapy. Frequent relapses, however, demonstrate that the bioactivity of these mAbs is still suboptimal. The concept of improving the anti-tumor activity of mAbs is well established and potentiating the cytotoxicity induced by anticancer mAbs can be achieved by strategies that target the downstream cytolytic effector cells. The recruitment of Fcγ receptor-dependent functions appears well suited in this regard, because several lines of evidence suggest that enhancing antibody-dependent cellular cytotoxicity (ADCC) induced by therapeutic mAbs may directly improve their clinical efficacy. The cytolytic effector cells involved in ADCC are FcγR-expressing natural killer (NK) cells, but also γδ T cells can be amplified and finetuned for stronger ADCC activity. γδ T cells are raising a considerable interest in the immunotherapy community given their intrinsic antitumor activity that can be boosted by stimulation with synthetic phosphoantigens (PAgs), or with drugs that cause their accumulation into target cells, like aminobisphosphonates (N-BPs), and low doses interleukin (IL)-2. The field is interesting, and several papers have already explored this approach in solid and haematological malignancies. Thus, we propose that enhancing the efficacy of mAbs by combination with γδ T cell activation may have considerable therapeutic potential for a variety of malignancies, most especially for patients whose FcγR alleles impair ADCC.

The aim of our study was to evaluate the capability of a crude extract of phenols from extra virgin olive oil of Moraiolo cultivar to induce apoptosis and/or differentiation in sensitive and resistant HL60 cell lines to anticancer drugs (Typical Multidrug Resistance). Our data highlight that the crude extract is able to induce apoptosis on both sensitive and resistant cells, whereas the exposure to a number of anticancer drugs does not induce apoptosis in resistant cells. In differentiation experiments we investigated the capability of crude extract of phenols to induce the expression of CD11 granulocytic or CD14 monocytic cell surface antigen in sensitive and resistant HL60 cell lines. At IC50 dose level (17 µg/ml and 32 µg/ml respectively for sensitive and resistant cell lines), the crude extract induced differentiation associated with the expression of CD14 monocytic cell surface antigen either in sensitive or resistant cell lines but not that of CD11 granulocityc cell surface antigen. Further investigations are in progress to better clarify the mechanism by which olive oil phenols induce differentiation differentiation on this cell line.

BACKGROUND: The T-cell lymphoma cell line HuT78B1, selected for resistance to Fas-mediated apoptosis, resulted unexpectedly resistant to the apoptotic and cytotoxic effects of gemcitabine (dFdC). We investigated whether this resistance was due to the impairment of the Fas/Fas-ligand (FasL) system. MATERIALS AND METHODS: dFdC effects were studied in HuT78B1 and in the parental Fas-sensitive HuT78 cells exposed to inhibitors of the Fas/FasL system. RESULTS: FasL- and Fas-blocking antibodies did not interfere with dFdC-induced apoptosis in HuT78 cells, whereas inhibitors of caspase-8, -9, -1 or -3 had partial inhibitory effects. Notably, in HuT78B1 cells there was a markedly reduced dFdC accumulation notwithstanding a high activity of the activating enzyme deoxycytidine kinase. dFdC accumulation in HuT78 cells was unaffected by a Fas-blocking antibody. CONCLUSION: This is the first time that the selection of a Fas-resistant cell line led to the isolation of a cell clone unable to accumulate the deoxycytidine analog dFdC. Our results show that this alteration is independent from the impairment of the Fas/FasL system.

To further explore the SAR of resveratrol-related trans-stilbene derivatives, here we describe the synthesis of (a) a series of 3,5-dimethoxy analogues in which a variety of substituents were introduced at positions 2', 3', 4', and 5' of the stilbene scaffold and (b) a second group of derivatives (2-phenylnaphthalenes and terphenyls) that incorporate a phenyl ring as a bioisosteric replacement of the stilbene alkenyl bridge. We thoroughly characterized all of the new compounds with respect to their apoptosis-inducing activity and their effects on the cell cycle. One of the new derivatives, 13g, behaved differently from the others, as it was able to block the cell cycle in the G(0)-G(1) phase and also to induce differentiation in acute myelogenous leukemia HL60 cells. Compared to resveratrol, the synthetic terphenyl 13g showed a more potent apoptotic and differentiating activity. Moreover, it was active on both multidrug resistance and Bcr-Abl-expressing cells that were resistant to resveratrol.

Pterostilbene and 3,5-hydroxypterostilbene are the natural 3,5-dimethoxy analogs of trans-resveratrol and piceatannol, two compounds which can induce apoptosis in tumor cells. In previous studies we demonstrated the importance of a 3,5-dimethoxy motif in conferring pro-apoptotic activity to stilbene based compounds so we now wanted to evaluate the ability of pterostilbene and 3,5-hydroxypterostilbene in inducing apoptosis in sensitive and resistant leukemia cells. When tested in sensitive cell lines, HL60 and HUT78, 3'-hydroxypterostilbene was 50-97 times more potent than trans-resveratrol in inducing apoptosis, while pterostilbene appeared barely active. However, both compounds, but not trans-resveratrol and piceatannol, were able to induce apoptosis in the two Fas-ligand resistant lymphoma cell lines, HUT78B1 and HUT78B3, and the multi drug-resistant leukemia cell lines HL60-R and K562-ADR (a Bcr-Abl-expressing cell line resistant to imatinib mesylate). Of note, pterostilbene-induced apoptosis was not inhibited by the pancaspase-inhibitor Z-VAD-fmk, suggesting that this compound acts through a caspase-independent pathway. On the contrary, 3'-hydroxypterostilbene seemed to trigger apoptosis through the intrinsic apoptotic pathway: indeed, it caused a marked disruption of the mitochondrial membrane potential delta psi and its apoptotic effects were inhibited by Z-VAD-fmk and the caspase-9-inhibitor Z-LEHD-fmk. Moreover, pterostilbene and 3'-hydroxypterostilbene, when used at concentrations that elicit significant apoptotic effects in tumor cell lines, did not show any cytotoxicity in normal hemopoietic stem cells. In conclusion, our data show that pterostilbene and particularly 3'-hydroxypterostilbene are interesting antitumor natural compounds that may be useful in the treatment of resistant hematological malignancies, including imatinib, non-responsive neoplasms.

Hsp90 is considered an interesting therapeutic target for anticancer drug development. Here we describe a new class of 4,5,6,7-tetrahydro-isoxazolo-[4,5-c]-pyridine compounds. A small library of derivatives has been synthesized and investigated. Some reported compounds show interesting properties combining both notable binding to Hsp90 and potent cell growth inhibitory activity. N-5 substitution with a 2,4 resorcinol carboxamide appears crucial for activity. Moreover, a derivative bearing a hydroxamic acid residue bound to C-3 amide portion was found to inhibit both Hsp90 and HDAC6.

During a screening for compounds that could act against Mycobacterium tuberculosis, a series of new cellular antiproliferative agents was identified. The most cytotoxic molecules were evaluated against a panel of human cell lines derived from hematological and solid human tumors. In particular, (E)-2-(1H-benzo[d] [1,2,3]triazol-1-yl)-3-(4-methoxyphenyl)acrylonitrile (1) was found to be of a potency comparable to etoposide and greater than 6-mercaptopurine in all cell lines tested. Accordingly, a synthesis of a new series of (E)-2-(5,6-dichloro-1H-benzo[d] [1,2,3]triazol-1-yl)-3-(4-R-phenyl)acrylonitriles was conducted in order to extend the studies of structure-activity relationship (SAR) for this class of molecules. With the aim to evaluate if 3-aryl-2-[1H-benzotriazol-1-yl]acrylonitriles were able to act like tubulin binding agents, the effects on cell cycle distribution of the most active compounds (1, 2a, 3 and 4) were analyzed in K562 cells. A detailed molecular modeling study of the putative binding mode of this series of compounds on tubulin is also reported.

New terphenyl derivatives have been synthesized and tested for their effect on cell survival in serum-free cultures. These compounds protected HL60 cells from death and supported their growth with an activity higher than that of the natural 14-hydroxy-retro-retinol. Terphenyls 26 and 28 also possess antiapoptotic activity on neuronal cells, proving them as possible candidates for the treatment of neurodegenerative and ischemic diseases.

BackgroundChagas disease, also known as American trypanosomiasis, is a potentially life-threatening illness caused by the protozoan parasite Trypanosoma cruzi. No progress in the treatment of this pathology has been made since Nifurtimox was introduced more than fifty years ago and is considered very aggressive and may cause several adverse effects. Currently, this drug has severe limitations, including high frequency of undesirable side effects and limited efficacy and availability and the research to discover new drugs for the treatment of Chagas disease is imperative. Many drugs available in the market are natural products as found in nature or compounds designed based on the structure and activity of these natural products.Methodology/Principal FindingsThis study evaluated the in vitro antiparasitic activity in T. cruzi epimastigotes and intracellular amastigotes of a series of stilbene and terphenyl compounds previously synthesized. The action of the most selective compounds has been investigated by flow cytometry analysis to evaluate the mechanism of cell death. The ability to induce apoptosis or caspase-1 inflammasome were assayed in macrophages infected with T. cruzi after treatment comparing with Nifurtimox.Conclusions/SignificanceThe stilbene ST18 was the most potent compound of the series. It was slightly less active than Nifurtimox in epimastigotes but most active in intracellular amastigotes. Compared to Nifurtimox, it was markedly less cytotoxic when tested in vitro on normal cells. ST18 was able to induce a marked increase of parasites positive to Annexin V and monodansylcadaverine. Moreover, ST18 induced the activation in infected macrophages of caspase-1, a conserved enzyme which plays a main role in controlling parasitemia, host survival, and the onset of adaptive immune response in Trypanosoma infection. The antiparasitic activity of ST18 together to its ability to activate caspase-1 in infected macrophages and its low toxicity on normal cells makes this compound interesting for further clinical investigations.Author SummaryChagas disease is a pathology caused by the protozoan parasite Trypanosoma cruzi. No progress in the treatment of this pathology has been made since benznidazole and Nifurtimox were introduced more than fifty years ago. However, these drugs have severe limitations and the research to discover new drugs for the treatment of Chagas disease is imperative. We evaluated the in vitro antiparasitic activity in T. cruzi epimastigotes of a series of stilbene and terphenyl compounds previously synthesized. The stilbene ST18 was the most potent compound of the series. It was slightly less active than nifurtimox in epimastigotes but most active in intracellular amastigotes. Compared to Nifurtimox, it was markedly less cytotoxic when tested in vitro on normal cells. ST18 was able to induce a marked increase of parasites positive to Annexin V and monodansylcadaverine. Moreover, this compound induced the activation in infected macrophages of caspase-1, an evolutionarily conserved enzyme which plays a main role in controlling parasitemia, host survival, and the onset of adaptive immune response in T. cruzi infection. The antiparasitic activity of ST18 together to its ability to activate caspase-1 in infected macrophages and its low toxicity on normal cells makes this compound interesting for further clinical investigations.

Mediterranean spotted fever (MSF) is endemic in Italy, where Rickettsia conorii subsp. conorii was thought to be the only pathogenic rickettsia and Rhipicephalus sanguineus the vector and main reservoir. R. conorii subsp. israelensis, which belongs to the R. conorii complex, is the agent of Israeli spotted fever (ISF); apart from Israel, it has also been found in Italy (Sicily and Sardinia) and in different regions of Portugal. We describe here two severe cases of ISF which occurred in otherwise healthy Italian adults. Their characteristics are analyzed and discussed in the light of other 91 cases found through a systematic review of international literature.

Based on the encouraging results found for 3,5-dimethyl-6-phenyl-8-(trifluoromethyl)-5,6-dihydropyrazolo[3,4-f][1,2,3,5]tetrazepin-4-(3H)-one 7 previously tested by us, as well as the consideration that heterocycle fused tetrazepinones bearing the 2-chloroethyl substituent show a better cytotoxic profile than temozolomide and mitozolomide against human cancer cell lines which express the DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT), in this paper we report the multistep synthesis and the biological study of 3-(2-cloroethyl)-5-methyl-6-phenyl-8-(trifluoromethyl)-5,6-dihydropyrazolo[3,4-f][1,2,3,5]tetrazepin-4-(3H)-one 10. Like compound 7, it was active on P-glycoprotein expressing cells (MDR) HL60 and on K562 cell line that are resistant to apoptosis induced by different stimuli, showing GI50 values of 14 and 18 µM respectively. As an antiproliferative agent against the above cells compound 10 was about 2.2 times more active than compound 7. Compound 10 was also tested against WiDR cells which are overexpressing the DNA repair protein MGMT, showing a GI50 value of 2.3 µM. Finally, concerning the effect on cell cycle we observed an evident difference between compounds 7 and 10. In fact, compound 7 induces a block of cell cycle in G0-G1, therefore acting as phase-specific drug, in contrast, compound 10 is a not phase-specific agent. Both the compounds are able to increase the apoptotic sub G0-G1 peak of cell cycle.

Most of the antileishmanial modern therapies are not satisfactory due to high toxicity or emergence of resistance and high cost of treatment. Previously, we observed that two compounds of a small library of trans-stilbene and terphenyl derivatives, ST18 and TR4, presented the best activity and safety profiles against Leishmania infantum promastigotes and amastigotes. In the present study we evaluated the effects of ST18 and the TR4 in 6 different species of Leishmania and the modifications induced by these two compounds in the production of 8 different cytokines from infected macrophages. We observed that TR4 was potently active in all Leishmania species tested in the study showing a leishmanicidal activity higher than that of ST18 and meglumine antimoniate in the most of the species. Moreover, TR4 was able to decrease the levels of IL-10, a cytokine able to render the host macrophage inactive allowing the persistence of parasites inside its phagolysosome, and increase the levels of IL-1β, a cytokine important for host resistance to Leishmania infection by inducible iNOS-mediated production of NO, and IL-18, a cytokine implicated in the development of Th1-type immune response.

With the aim of enhancing the structural complexity and diversity of an existing collection of bi- and terphenyl compounds, we synthesized hybrid molecules comprising of spirocyclic ketones (a complexity-bearing core) and bi/terphenyls (privileged fragments). Compounds 1, 3, 4, and 6 showed well-defined activity on apoptosis and differentiation, making them potential leads for development as new anticancer agents and chemical probes to study signaling networks in neoplastic cells.

The multistep synthesis of 3,5-dimethyl-6-phenyl-8-(trifluoromethyl)-5,6-dihydropyrazolo[3,4-f][1,2,3,5]tetrazepin-4(3H)-one 15 has been carried out. The compound showed antiproliferative and apoptotic effects against K562, K562-R (imatinib mesilate resistant), HL60 and multidrug resistant (MDR) HL60 cell lines. Compound 15 showed a pro-apoptotic activity against HL60 and K562 resistant cell lines markedly higher than etoposide and busulfan, respectively. Flow cytometry studies carried out on K562 cells allowed to establish that 15 induces G0-G1 phase arrest followed by apoptosis.

Resistance to imatinib mesylate is an emergent problem in the treatment of Bcr-Abl expressing myelogenous leukemias and additional therapeutic strategies are required. We observed that galangin, a non-toxic, naturally occurring flavonoid was effective as anti-proliferative, and apoptotic agent in Bcr-Abl expressing K562 and KCL22 cells and in imatinib mesylate resistant K562-R and KCL22-R cells. Galangin induced an arrest of cells in G0–G1phase of cell cycle and a decrease in pRb, cdk4, cdk1, cycline B levels; moreover, it was able to induce a monocytic differentiation of leukemic Bcr-Abl+ cells. Of note, galangin caused a decrease in Bcl-2 levels and markedly increased the apoptotic activity of imatinib both in sensitive or imatinib-resistant Bcr-Abl+ cell lines. In contrast, flavonoids unable to modify the Bcl-2 intracellular levels, such as fisetin and chrysin, did not increase the apoptotic effect of imatinib. These data suggest that galangin is an interesting candidate for a combination therapy in the treatment of imatinib-resistant leukemias.

Failure to perform the Fas-related apoptosis pathway can account for tumor resistance both to chemotherapeutic agents and to immunological effectors. We studied the role of NK-kappaB in Fas-resistance, employing the Fas-sensitive human T-lymphoma HuT78 cell line and its Fas-resistant variants HuT78B1 and HuT78G9. All these cell lines expressed high levels of constitutively activated NF-kappaB. Pretreatment of cells with NF-kappaB inhibitors (PDTC, MG132, or SN50) strongly enhanced CH11-induced apoptosis in HuT78 and Hut78G9 cells, while only MG132 showed a similar potentiating effect in HuT78B1. The described synergism was significantly inhibited by pretreatment with the anti-Fas-blocking antibody ZB4 or with the pancapsase inhibitor Z-VAD-FMK, but not by capsase-8 or -9 inhibitors. Overall, these data suggest that NF-kappaB inhibition may restore the Fas-pathway in Fas-resistant NF-kappaB-overexpressing tumors.

Background Studies of the apoptosis mechanisms involved in the pathogenesis of tuberculosis have suggested that Mycobacterium tuberculosis can actively interfere with the apoptosis of infected cells. In vivo studies have been performed in adult populations but have not focused on this process in children. In the present study, we analyzed spontaneous T lymphocyte (PBT) apoptosis in the peripheral blood of children with central nervous system tuberculosis (CNS TB), before and after chemotherapy, and compared the results with healthy controls. Methods A case-control study was conducted from January 2002 to June 2009. It included 18 children with CNS TB and 17 healthy controls. Spontaneous apoptosis of PBTs, including CD4+, CD8+ and CD8+/CD28+ T cells, was evaluated after 24 and 72 h of culture in complete medium, using the Annexin V detection test. Analysis was conducted before and after chemotherapy, and expression of the apoptotic markers CD95 (Fas) and Fas ligand (FasL) was evaluated. Results Higher percentages of apoptotic T cells and CD4 lymphocytes were isolated from children with acute phase CNS TB than from children in the control group (p < 0.05). This difference significantly decreased after 60 days of specific treatment. In children with CNS TB, high levels of Fas ligand expression were detected in lymphocyte populations, associated with a high percentage of Fas positive cells, before and after treatment. In contrast to the CD4+ apoptosis profile, we did not find any significant difference in total CD8+ cell apoptosis between children with acute phase disease and the control group. However, the percentage of apoptotic CD8+/CD28+ T cells was significantly higher in the children with acute phase disease than in the healthy controls. Conclusions Our findings indicate that CNS TB in pediatric patients increases the sensitivity of CD4 and CD8+/CD28+ T cells to apoptosis, suggesting a hypoergic status of this infection. This could play a key role in the immunopathogenesis of this complicated form of TB. Interestingly, specific chemotherapy is able to normalize both apoptosis sensitivity and T-cell activation.

The central role of microtubules in cell division and mitosis makes them a particularly important target for anticancer agents. On our early publication, we found that a series of 2-(3',4',5'-trimethoxybenzoyl)-3-aminobenzo[b]thiophenes exhibited strong antiproliferative activity in the submicromolar range and significantly arrested cells in the G2-M phase of the cell cycle and induced apoptosis. In order to investigate the importance of the amino group at the 3-position of the benzo[b]thiophene skeleton, the corresponding 3-unsubstituted and methyl derivatives were prepared. A novel series of inhibitors of tubulin polymerization, based on the 2-(3,4,5-trimethoxybenzoyl)-benzo[b]thiophene molecular skeleton with a methoxy substituent at the C-4, C-5, C-6 or C-7 position on the benzene ring, was evaluated for antiproliferative activity against a panel of five cancer cell lines, for inhibition of tubulin polymerization and for cell cycle effects. Replacing the methyl group at the C-3 position resulted in increased activity compared with the corresponding 3-unsubstituted counterpart. The structure-activity relationship established that the best activities were obtained with the methoxy group placed at the C-4, C-6 or C-7 position. Most of these compounds exhibited good growth inhibition activity and arrest K562 cells in the G2-M phase via microtubule depolymerization. ispartof: Bioorganic & Medicinal Chemistry vol:18 issue:14 pages:5114-5122 ispartof: location:England status: published

Two new series of inhibitors of tubulin polymerization based on the 2-amino-3-(3,4,5-trimethoxybenzoyl)benzo[b]thiophene molecular skeleton and its 3-amino positional isomer were synthesized and evaluated for antiproliferative activity, inhibition of tubulin polymerization, and cell cycle effects. Although many more 3-amino derivatives have been synthesized so far, the most promising compound in this series was 2-amino-6-methyl-3-(3,4,5-trimethoxybenzoyl)benzo[b]thiophene, which inhibits cancer cell growth at subnanomolar concentrations and interacts strongly with tubulin by binding to the colchicine site.

New effective cytotoxic agents and combinations are urgently needed in cancer treatment. The enzyme inosine monophosphate dehydrogenase is a potentially useful target for drug development, since its activity has been shown to be amplified in malignant cells. Thiophenfurin, an inhibitor of the enzyme synthesized by us, is endowed with a significant apoptotic activity in promyelocytic leukaemia HL60 cells. Since retinoids were successfully employed in the treatment of patients with leukaemia, demonstrating significant differentiation-inducing and apoptotic effects, we carried out this study to evaluate the effects of the combination of thiophenfurin and several retinoid molecules, acting in different phases of the cell cycle in vitro. The results show that thiophenfurin is capable of eliciting significant S phase-specific antiproliferative effects in different sensitive and resistant cell lines with the IC50s ranging from 6.7 to 26 microM. When HL60 cells were treated with thiophenfurin in combination with retinoids, the effects on cell growth were additive or synergistic, depending on the kind of retinoid used and the sequence of treatment. In particular, we observed additive effects when the cells were exposed to thiophenfurin and all-transretinoic acid either simultaneously or sequentially. Instead, when the new heterocyclic retinoid isoxazole benzoic acid was used, synergism was obtained in the cells treated sequentially. The combination of thiophenfurin and isoxazole benzoic acid determined synergistic apoptotic effects through a mitochondrion-dependent mechanism, suggesting the possible usefulness of this combination in the treatment of leukaemia.

This study evaluated the level of susceptibility of monocytes and lymphocytes to spontaneously induced and CH11-induced apoptosis in 16 patients with Brucella infection. The expression of some immunological and apoptotic markers was evaluated. Before therapy, monocytes showed a high level of resistance to spontaneously induced or CH11-induced apoptosis in all patients. In patients with acute infection, this resistance persisted for 10-20 days after treatment was initiated, then decreased; in chronically infected patients, it persisted after 45 days of treatment. Lymphocytes were also more resistant to CH 11-induced apoptosis. The level of activated CD8++ T lymphocytes was high in patients with acute infection. The data indicate that the CD95-mediated apoptotic pathway is not involved in CH11 resistance. Lymphocytes are not infected by Brucella, so their resistance to apoptosis may be due to a soluble factor released by infected monocytes. The evaluation of levels of susceptibility to CH11-induced apoptosis in monocytes may be used to test the effectiveness of the therapy.